Faulty Rivets Emerge as Clues To Titanic Disaster

By WILLIAM J. BROAD

Published: January 27, 1998

EVER since the Titanic was discovered in the depths of the North Atlantic a dozen years ago, her steel plates melting into rivers of rust, expeditions have repeatedly probed the hulk. And investigators armed with a growing body of evidence have been working to solve riddles posed by the opulent liner's sinking.

The ship, of course, was moving too fast through a sea of towering ice when it struck a large floe on its inaugural voyage in 1912. But much uncertainty has surrounded the exact nature of the damage and whether it might have been avoided in whole or part if the ship's design or construction had been different, perhaps preventing the loss of more than 1,500 lives.

Now, after years of analysis and any number of false leads, experts say they have preliminary evidence suggesting that the Titanic, the biggest ship of her day, a dream of luxury come to life, may have been done in by structural weaknesses in some of her smallest and least glamorous parts: the rivets.

Two wrought-iron rivets from the Titanic's hull were recently hauled up from the depths for scientific analysis and were found to be riddled with unusually high concentrations of slag, making them brittle and prone to fracture.

''We think they popped and allowed the plates to separate and let in the water,'' said William H. Garzke Jr., a naval architect who heads a team of marine forensic experts investigating the disaster.

The rivet analysis, which Mr. Garzke and other experts said must be considered tentative because of the small number of rivets sampled, sheds light on findings made public last year. Experts, diving down nearly two and a half miles to peer through thick mud with sound waves, discovered that the Titanic's bow had been pierced by six thin wounds, the damage apparently done as hull seams were forced open. The finding laid to rest the myth that the iceberg had sliced open a 300-foot gash in the ship's side and strengthened interest in the possibility of rivet failure.

The new analysis was done by Dr. Timothy Foecke, a metallurgist at the National Institute of Standards and Technology, a Federal agency in Gaithersburg, Md. It helps set industry standards and employs some of the Government's top metallurgists.

Working with Mr. Garzke, who is chairman of the marine forensics panel of the Society of Naval Architects and Marine Engineers, a professional group based in Jersey City, Dr. Foecke analyzed the two Titanic hull rivets, cutting them in half and probing their composition with tools like microscopes and image analyzers. His work revealed an overabundance of slag, the glassy residue left over from the smelting of metallic ores.

''The microstructure of the rivets is the most likely candidate for becoming a quantifiable metallurgical factor in the loss of Titanic,'' Dr. Foecke concludes in a report, ''Metallurgy of the R.M.S. Titanic,'' to be formally released early next month.

In the report and interviews, Dr. Foecke said the slag content of the rivets was more than three times as high as is normally found in modern wrought iron, making it less ductile and more brittle. While it is not clear whether a better grade of rivets would have saved the ship, he said, the developing evidence points in that direction.

It is also unclear whether such high concentrations of slag were typical for the era of the Titanic's construction, from 1909 to 1912. But some historical evidence suggests that the excessive levels might have been abnormal, raising the issue of culpability.

The Titanic's builder, Harland & Wolff, would make no comment on the findings, saying the topic was too old. ''We don't have an archivist or anything like that,'' said Peter Harbinson, a spokesman for the company, in Belfast, Northern Ireland. ''We don't have anybody in a position to comment.''

The luxury liner was built for the White Star Line, a company that no longer exists because it merged with Cunard in the Depression.

Even if shoddy workmanship became a major issue, which would require the analysis of more Titanic rivets and more comparisons with the practices of the day, historians say that all issues of liability were settled long ago.

Addressing a more recent issue, experts say the rivet finding has no link to ''Titanic,'' the $200 million epic now playing in movie theaters. But both the finding and the movie demonstrate independently how advanced technology is opening up the sea's depths.

The Hollywood director James Cameron went down in a Russian submersible in 1995 to film the wreck. A year later, a different expedition used a French submersible to retrieve a number of artifacts, including the hull rivets.

That work is now opening a new chapter in the long investigation of why the ship, proclaimed unsinkable, went down so fast.

The 46,000-ton Titanic was made of steel held together with some three million rivets. They secured both beams and plates. Each rivet was formed at a factory into a mushroom shape; it was heated at the work site to incandescent temperatures and then inserted into the aligned holes of plates and beams. The glowing-hot end, or tail, was then hammered down to lock the parts firmly together.

The rivets were made of wrought iron, which contains some slag. This contaminant is useful because pure iron is very ductile, bending easily without breaking. Slag gives it added strength. Slag is fused dross that tends to separate from a metal during smelting. It is made largely of silicon, the main ingredient of rock, sand and glass. In wrought iron of high quality, slag is distributed finely and evenly in long microscopic threads. But too much of it can make the iron brittle, like glass.

Suspicions of rivet failure have long haunted the famous disaster, along with other possible culprits. The first hard evidence emerged only after the wreck was discovered in 1985, a ghost ship seemingly frozen in time. In 1986, the explorer Robert D. Ballard visited the grave site in a submersible and saw ''plates knocked apart at their riveted seams.''

But mysteries remained because the area in the lower bow damaged by the iceberg remained hidden under thick layers of mud.

The detective work turned away from rivets after expeditions in the late 1980's and early 1990's picked up Titanic parts and artifacts. Analysis showed that the hull plates were made of mediocre steel that was apt to fracture in cold water, suggesting that the iceberg caused wide cracking.

But the French expedition of 1996 found two tantalizing clues that undercut that theory.

The first was discovered by David Livingstone, an official from Harland & Wolff who dove down to the wreck. He found a bend of about 90 degrees where the port side had crumpled as the ship slammed into the bottom. That suggested that the hull steel had a substantial degree of flexibility.

The second finding was made by sonar experts who probed the starboard side of the lower hull where the iceberg struck, an area buried in mud up to 55 feet deep. Their readings disclosed six narrow slits.

''They appear to follow the hull plate,'' Paul K. Matthias, president of Polaris Imaging Inc. in Narragansett, R.I., who did the sonar work, said afterward. In early 1997, he speculated that the gaps had probably been created when rivets along plate seams had popped open, creating slits no wider than a person's hand.

Both findings were made under the auspices of the marine society forensics panel. Dr. Foecke, of the National Institute of Standards and Technology, a panel expert investigating the makeup of Titanic's hull steel, became intrigued by the new findings and obtained two hull rivets, cutting them apart with a diamond saw.

He was surprised when his inquiry disclosed 9.3 percent slag in one rivet and similar levels in the other. By contrast, modern wrought iron has a slag content of 2 percent or 3 percent.

What was acceptable in the Titanic's day? Rummaging through old books, Dr. Foecke found a 1906 entry for ''medium quality'' wrought iron. He analyzed a picture of the material and found that its slag content was from 2 percent to 2.5 percent, much lower than the Titanic rivets.

But he said in an interview that ''as far as I can tell, there was no standard of the time'' for the amount of slag in wrought iron.

Complicating the picture, Dr. Foecke found that the slag of the Titanic rivets was very coarsely distributed, creating lines of weakness. Most surprising, its grain changed abruptly just before the area where the ends popped off, turning perpendicular to the axis grain and suggesting an area of major weakness.

The grain might have been turned to the side, he said, when rivet ends were hammered too hard.

Dr. Foecke said that the examined rivets, though flawed by today's standards and suspicious by virtue of old evidence, had conceivably been ''state of the art back then.''

And both he and Mr. Garzke, the forensics panel's chairman, cautioned that a dozen or more Titanic rivets must eventually be analyzed to firm up the conclusions. An expedition this summer is to retrieve more rivets, they noted.

More historical evidence from other ships and documents is also needed, the experts stressed. Dr. Foecke said he now often found himself in the ''rusty, musty'' part of the library at the National Institute of Standards and Technology.

Both experts added, however, that some corroborative evidence existed. For instance, a Titanic crew member who survived testified about seeing water rushing through a riveted seam, between plates that had sprung open.

More evidence comes from the Titanic's sister ship, the Olympic, which collided in 1911 with a small warship, receiving relatively minor but revealing damage. ''You can count 37 missing rivets,'' Mr. Garzke said, referring to an old photograph of the Olympic's wound.

George Tulloch, president of R.M.S. Titanic of New York City, the company that organized the 1996 French expedition and is raising parts of the ship, expressed doubt about the metallurgic analysis, saying rivets in the damaged area might, by design, have been made differently from the analyzed ones.

But Dr. Foecke said wrought iron used for the Titanic's rivets was undoubtedly meant to be chemically uniform. The outstanding question, he added, was whether the two analyzed rivets were accidental oddballs or ''representative of the class.''

Paul Louden-Brown, a British maritime historian and author of ''The White Star Line'' (Ship Pictorial Publications, 1991), said in an interview that rivet failure was much more likely than hull-plate fracture. But he contended that Harland & Wolff, the ship's maker, had no incentive to scrimp on rivets because the Titanic was built on a cost-plus contract. All the liner's materials, he said, were ''absolutely top-notch.''

Dr. Foecke speculated that the rivet shortcomings, if confirmed to be widespread, had perhaps grown out of the hectic circumstances of the day rather than any kind of conscious decision to cut corners. From 1908 to 1914, the shipyard, he noted, was struggling to build three behemoths: the Titanic, Olympic and Britannic. Construction of the Titanic was even stopped at one point while emergency repairs were made to the Olympic after her collision.

In this frenzy of building and repair, he said, rivet-making plans might have slowly and almost unknowingly been compromised. ''We have no way of knowing,'' he stressed. ''That's conjecture.''

He also said there was currently no way of knowing whether a better grade of rivets would have withstood the iceberg's blow and prevented or limited the great loss of life.

But Dr. Foecke said the current state of the evidence, while ambiguous, suggested such a possibility.

''It might have turned out differently,'' he said.

Photos: Dr. Timothy Foecke, a scientist at the National Institute of Standards and Technology, holding a Titanic rivet that he analyzed. Faulty rivets may account for six tears recently discovered in ship's lower bow. (The New York Times; Illustration by Gorka Sampedro)(Marty Katz for The New York Times)(pg. F5); Capt. Edward J. Smith looked down from high atop the Titantic just before her inaugural Atlantic crossing. She was docked in Queenstown, on the south coast of Ireland, taking on her last passengers. (pg. F1) Chart: ''Why the Unsinkable Went Down'' Millions of rivets held Titanic together. Now new evidence suggests that they were defective and that the collision with the iceberg, rather than cutting a gash in the hull, caused the rivets to pop. An analysis shows they had high concentrations of slag, a glassy material, making them brittle and prone to fractures. The hammered ends, or tails, of the analyzed rivets have vanished. They presumably popped off during the disaster. 1. Wrought-iron rivets were inserted from the outside through steel hull plates and their ends were then hammered flat on the inside to make a tight fit. 2. The hammered ends of the rivets popped off when the ship struck the iceberg, a new study suggests. Rivets from the sunken ship were cut in two and analyzed, revealing heavy grains of weakening slag, visible as dark streaks in microscopic views, right. Slag grain near the hammered end abruptly turns perpendicular to the axis, suggesting an area of major weakness. Slag grain in the rivet's center runs parallel to the axis. Chart illustrates the faulty rivets. (Source: Dr. Timothy Froecke, National Institute of Standards and Technology)(Illustration by Gorka Sampedro)(pg. F1)